The present invention relates generally to valves, and relates more specifically to a novel valve construction that provides many improved features over the prior art, and is well adapted for medical usage, such as in needleless IV sets, and other medical applications where it is desirable to avoid use of needles in the transmission and delivery of fluid products to patients in a sterile environment.
Presently, there are many types of swabable valves designed to address needlesticks safety issues. Such valves must satisfy many requirements. For example, they must safely withstand, without loss of performance, at least 100 connects and disconnects to an injection site before the set is replaced. In addition, that connection shall be maintained for an extended period of time before disconnection is made. Still, the site shall be capable of accepting subsequent connections without allowing any leakage. Such valves must seal against pressurized fluid within a set. They must withstand pressures in excess of, for example, 25 p.s.i., for a short time, such as during an injection made through an adjacent site or if a pump is nearby. Such valves shall not contain any dead space where fluid can collect and not be readily flushed away. Also, priming volume should be minimized. Furthermore, they must also be easily accessible by standard luer connectors and provide secure locking features, so such connectors could be left connected to the site without further assistance from a practitioner. Further, such valves shall be manufactured at high speeds and low cost. At the same time, the design must allow for minimal manufacturing defects. Still further, it is desirable that such valves have as few components as possible, and be easily assembled, without requiring any difficult component orientation or positioning. Another highly desirable feature is easy and safe swabability of the valve inlet area.
Most current valves restrict free flow of passing fluid by employing narrow passages, ribs or internal cannula-like features. Restricting the flow path in such a manner may create conditions for hemolytic damage. Such restrictions also make the valve generally more difficult to flush. Examples of some valves are shown in U.S. Pat. Nos. 6,325,782 and 6,290,206.
Further, some valves"" stems or seals employ an opening that is closed upon assembly. This opening must be produced during molding, and requires a core pin to extend all the way through the part, creating a possibility for flash to develop at the core pin shut off area. Such flash would then be found at the proximal end of the stem and present a possible danger if removed by the action of a penetrating luer connector as this would case the flash to be pushed into the fluid flow path.
Moreover, valves that employ resilient stems with a slit have an elliptical cross sectional geometry and slit orientation must be precisely controlled by positioning system during slit manufacture or during assembly. Examples of this type of valve is shown in U.S. Pat. Nos. 6,050,978 and 5,354,275.
Furthermore, in medical applications, it is usually desirable to prevent the patient from being exposed to the fluid which is being injected to or extracted from the patient, and it is desirable to insulate nurses and doctors from exposure to the liquid which may contain the patient""s blood or waste products. However, often the instrument used to inject or withdraw the fluid (which is generally the male component of the syringe), retains some of the fluid on the tip thereof, thus providing a risk to nurses and doctors of being exposed to the fluid. Wiping off this fluid prior to disconnecting the instrument is highly desirable.
Still further, some similar devices currently on the market employ thin ribs or cannula-like housing details, which might be susceptible to breakage. Such breakage could damage the flexible sealing stem in the valve, or the flash could become loose inside the flow path. The same ribs or narrow housing channels present obstacles for smooth fluid flow, thus restricting flow and, in the case of blood transfer, they increase the risk of mechanical hemolytic damage.
The present invention is directed to address at least some of the above-mentioned requirements, as well as undesirable characteristics of some current swabable valves.
A general object of the present invention is to provide a valve that seals itself to restrict fluid flow thereinto, and decreases the risk of contaminants such as bacteria collecting on or within the valve. All external surfaces in the proximity of the valve stem are accessible to be wiped clean with a sterile swab.
Another object of the present invention is to provide a valve which includes a stem that provides a relatively flat and wrinkle-free top surface which can be easily swabbed.
Another object of the present invention is to provide a valve which minimally restricts fluid flow therethrough without requiring fluid to pass narrow cannula like passages and also without any ribs like housing features, to provide valve structure with an unobstructive flow path allowing for smooth fluid flow without hemolytic damage and designed so, it will not present difficulty for molding and high speed assembly.
Still another object of the present invention is to provide a valve structure including a female valve component that seals with a male component or instrument when the instrument is engaged therewith so that there is no leakage of fluid.
Yet another object of the present invention is to provide a valve which automatically wipes or swabs the male component or instrument upon the instrument being disengaged or removed therefrom.
A still yet further object of the present invention is to provide a valve structure, and particularly a female valve that obtains an effective seal and does not have a tendency to leak fluid into the surrounding area upon the male component or instrument being disengaged therefrom.
Yet still another object of the present invention is to provide a valve structure that allows fluid flow in both directions upon a male component or instrument being engaged therewith.
Still another is to provide uniform circular cross sectional geometry for all components so there is no need for precise orientation for the purpose of slitting or assembly. Such construction will allow for highly reliable assembly without employment of sophisticated high speed positioning systems.
Briefly, and in accordance with the above, the present invention envisions a valve or female component that engages with a male component or instrument, where the valve includes a resilient, deformable stem which is located in a valve body and is shiftable therein. The valve stem has a slit, and is uniformly round, as is the housing (i.e., has a uniformly round cross-sectional profile). Additionally, the valve stem includes a circumferential notch on its exterior surface. The notch provides a point of weakness on the exterior surface of the valve stem. The notch is configured to provide that, when the male component or instrument is engaged with the valve, the valve stem buckles or expands generally outwardly, at the notch, thereby providing increased flow volume within the valve stem. When an instrument is engaged in the slit of the valve stem, the stem shifts in the valve body, and the slit seals against the outer surface of the instrument or male member, thus allowing liquid to flow through the stem, to or from the instrument. The structure of the valve is such that when the valve is actuated, fluid can flow in either direction through the valve. As the instrument is being removed from the stem, the slit in the valve stem closes, and this prevents fluid leak upon further removal of the instrument. Also, the stem configuration provides that the stem swabs or cleans the tip of the instrument upon the tip of the instrument being removed from the slit. The stem is further configured with a relieve feature at the proximal end to achieve relatively flat and wrinkle free top surface for an easy swabbing.